Nerve cell assemblies in circumscribed regions of the brain are pathologically, e.g. excessively synchronously, active in patients with neurological or psychiatric diseases such as Parkinson's disease, essential tremor, dystonia or obsessive compulsive disorders. In this case, a large number of neurons synchronously form action potentials, i.e. the participating neurons fire excessively synchronously. In a healthy person, in contrast, the neurons fire with a different quality, i.e. in an uncorrelated manner, in these brain areas.
Stimulation techniques have been developed for treating such diseases which directly counteract pathologically synchronous neural activity. In particular the coordinated reset (CR) stimulation is in this respect characterized by great therapeutic effectiveness and reliability (cf. e.g. “A model of desynchronizing deep brain stimulation with a demand-controlled coordinated reset of neural subpopulations” by P. A. Tass, published in Biol. Cybern. 89, 2003, pages 81 to 88). In order to directly develop a desynchronizing effect in circumscribed target zones of the brain, electrodes (e.g. deep electrodes) are implanted in these target zones and/or in fibrous zones associated therewith. It is of central importance for the effectiveness of the CR stimulation that the different stimulation contacts lie in the neural population to be stimulated and/or in fibrous zones associated therewith. Optimum CR stimulation can only be carried out using at least two stimulation contacts, more would be better (e.g. four and more). The optimum stimulation contacts are in particular to be selected in accordance with their actual stimulation effect on the neural population to be desynchronized. To date, there is no automatically functioning process which uses objective measurement parameters for selecting the N optimum stimulation contacts from a larger number M (where M>N) of stimulation contacts. The selection of suitable stimulation contacts and of the associated parameters (e.g. the stimulation amplitude) rather takes place by time-consuming trial and error. This trial and error process does not guarantee the optimum effectiveness of the invasive CR therapy since, on the one hand, (in particular with a larger number of stimulation contacts) not all possible stimulation sites in the brain are systematically examined and, on the other hand, the patients are stressed by long examinations so that the cooperation of the patients naturally suffers and the results of the testing become worse.